Even celebs have trouble staying fit sometimes! Carrie Underwood admits toExtrathat keeping her amazing figure is not an easy feat. “This is an Underwood family tradition,” Carrie, 26, joked as she poked her midsection.

“The rear… starts going in and out so I have to work really hard to have it stay where it’s supposed to be,” Carrie explained.

The former American Idol winner revealed her tricks to staying thin before she hosts the Country Music Awards on Wednesday.

“Get rid of the junk crap,” Carrie said. “Lots of water and vitaminwater — it’s got a lot of good stuff in it.”